Two-stroke-cycle engine



Jun 16, 1925.

L. H. HOUNSFIELD TWO-STROKE CYCLE ENGINE Filed Jan. 30, 1923 .mvnrroll;

MFm WM/y W Patented June 1,6, 1925.

UNITED. STATE LESLIE HAYWOOD nounsrrnnn, or CROYDON, ENGLAND.

'rwo-sraoKE-cYoLn ENGINE.

! Application filed January 30, 1923 Serial No. 615,801.

To all whom it may concern: i y

Be it known that I, LnsL'In HAYWOOD HOUNSFIELD, a subject of the King ofEngland, residing at Croydon, Surrey, England, have invented certain newand useful Improvements in Two-Stroke-Cycle Engines, of which thefollowing is a specification.

This invention relates to improvements in and connected with two-strokecycle engines of the three port type using crank chamber compression,and wherein the cylinders are connected in pairs at the combustionchamber' end and so constructed that the piston movement alone, withoutthe use of auxiliary valves, controlsan inlet port between thecarburettor and the crank-chamber, a transfer port leading from thecrank-chamber to the combustion space, and an exhaust port leading fromthe combustion space to the exhaust. In engines of this type the chargepasses through thecrank case before reaching the cylinders and in sodoing is liable to pick up lubricating oil, even in engines in whichlubrication is not effected by mixing the oil with the petrol or otherfuel. If the oil thus picked up is not separated from the fuel but isallowed to collect in the cylinders, theengines and plugs areliable tobecome foul and oil is wasted. The present invention, therefore, has forits object the production of an engine which fouls less readily, anduses less lubricating oil than do engines as heretofore constructed.

In carrying out the invention the engine is so constructed as to affordthe greatest possible opportunity for oil to separate and gravitate outof the charge into the crank chamber before the charge passes to thecombustion chamber, and is further so constructed that such oil as maypass into the I combustion space cannot remain there but must gravitateaway therefrom and pass direct out from the exhaust. More particularlythe engine is so constructed'that the fuel passage from the carburettorto the crank chamber contains no liquid collecting pockets, and inaddition isso constructed that the chargehaving entered the crankchamber (where the gas velocities are comparatively low) has to traverseit in an up ward direction before reaching the transfer port from thecrank chamber to the combustion chamber. Thus 'thebulk of the oil whichseparates out is caused to settle in the crank chamber, and by arrangingthe axes of the cylinders constituting each of the connected pairsapproximately horizontally, wlth the intake cylinder (i. e. the cylindercontaining i the piston which controls the new charge) above the exhaustcylinder (i. e. the cylinder containing the piston controlling theexhaust port), such oil asmay enter the combustion space is promptlydrained and blown away through thee);- haust. 1 i

In the accompanying drawings which.

Figure 2 represents a cross section on the line 22 of Figure 1, and

Figure 3 is a section on the line 33 of Figure 2.

Like reference numerals The transfer port or passage 10 leads from theupper part of the crank chamber '11 to the upper or intake cylinder 12,al-

though not necessarily from the highest point of the crank chamber, asthe highest pointunight be so, situated as to collect lubricating oilthrown from the moving parts. By arranging the passage 10 in the upperpart of the crank chamber the sepa ration of oil by gravity'isfacilitated, and by suitably choosing the disposition of the transferport with regard tot-he moving parts in the crank chamber, it ispossible to ensure thatoil cannot be thrown directly into the port. Anyoil OIBXCGSS fuel which may however pass through this transfer pas sageinto thev intake cylinder 12 readily gravitates through the intakecylinder into the exhaust cylinder 13, and thence out of the exhaustport 14 which is, in engines constructed according to this invention,situate in the lower side of the exhaust cylinder. The force of gravityis assisted by the intermittent rush of the gases passingthrough fromthe intake portto the exhaustport.

Four cylinder engines constructed according to'this invention consistconveniently of two two-cylinder units 15 and 16 arranged side by sideso that the axes of the two intake cylinders 12 and 17 are substantiallyin a horizontal plane above another horizontal plane containing-theaxes'of the exhaust cylinders 13 and 18.' The inlet pipe or passage 19from the carburettor may pass indicate like parts throughoutthedrawings.

Cit

in a substantially horizontal direction and about equidistant from theaxes of all the cylinders into a chamber containing ports 21 leadinginto the crank chamberg the ports being controlled by the skirt endsofthe exhaust pistons.

The passage from the"carburett(n' to the crank chamber is constructed soas to be free froin'pocltet's in which liquid'can collect,

lLllClSO'tllElt' any oil which may deposit drains down intothe'cran-kchamber, and by disposmg the inlet 131136, or passage 19-1ntlre mannerabove cle'scr1becl,"-tl1'e "carburetted mix- 'ture be'comes heat e'dbyreason of its proxnor'do 'they require -de-carbonizing. "Hence thedifficulty experienced with mosttwostroke engines; of obtaining sparkingplugs which can both resist oil and the'high tom-- peratures associatedwith such engines, is eliminated! 1. In a two-stroke"cycleinternal-combusnon, engine of the three-port type. having crank-case"compression of the combustible mixture the combination of a casinghaving a compres's on chamber in' the form of a crank-case -"there'in;aninta ke cylinder having a transfer port anclan exhaust cylinder havingan exhaust port within said casing,

bothof which cylinders open atone end into the-said crank-case, acombustion cham- ,be1' "comfmon-'to both cylinders at the end'thereofremote' from thecrank case,'the exhaust cylinder*haviug an inletport at the side/of itsexhaust portremote from the combustion chamben'aconduit connected to said inlet "port" ifo'r supplying. combustiblemi'xtu're thereto, a transfer passage putting the said transfer port inopen communication w'iththe-crankcase, a crank-shaft in said crank'caseyand pistons operable one in each cylinder and operativelyconnected to "said "crank-shaftand arranged to control said portsywhi'chsaidiports are so situated and the engine parts'r provided with saidports are'so constructed =thatthe combustible cha'rgeus compelled toflow to and through thepinlet' port to the transfer port along a pathwhich dra'ins' downwardlytowards the bottomofthe crank-caSe'aWay fromthe said conduit, and the. whole of said combustion space in allpositions of the pistons drains down from the transfer port to theexhaust port withoutencountering a liquid-collecting pocket.

2. In two-stroke cycle internal-combustion engine 'of'the three-porttype having crankcase compression of the combustible mixture, thecombination of a casing having a compression chamber in the form of acrankcase therein, an intake cylinder having a transfer port and anexhaust cylinder having an exhaustport within said casing, both of'whichcylinders open atone end into the said crank-case, a combustion chambercommon to both cylinders at the end thereof remote' from the crank-case,the exhaust cylinder having an inlet port at the sideof its exhaust portremote from the combustion chamber, a transfer passage putting the saidtransfer port in open communication with i the crank-case, 'a crankshaftin said crankcase; and-pistons operable one in each cylinder andopera'tively' connected to said crankshaft and arranged to control saidports,

which said ports are 'sosituated, and-the engine parts'provided withsaid ports are so constructed that the combustible charge is compelledto flow upwards in the crankcase from the inlet port tothe-transfer portalong a path which drains downwardly to Wards thebottom'ofthe crank-caseaway from thcsaid inlet and transfer ports, and the'wvhole of saidcombustionspace in all positions of the pistons drains down -to theexhaust port withoutencountering a liquidcolleeting pocket.

3. In a horizontal, two-stroke cycle, internal-combustion engine 'of thethree port type havingcrank-case compression of the combustible mixture;the combination of a casing having a compression chamber in the form ofa crank-case therein, a pair of parallel substantially horizontalcylinders within said casing, whereof one cylinder is arranged above theother and both open at one end'into saidacran-k case, a conibustionchamber conunonto bot-h cylinders atthe end thereof remote from thecrank-case, the lower cylinder haa 'ing only in its upper part an'inletport and "havingatthe side of the inlet port remote'from the crank-casean exhaust port, the upper cylinder having a transfer port whichcommunicates with the upper part of'the crank-case,- pistons operableone in each cylinder and arranged'to control saidports a crank-shaft insaid crank-case, and means operatively connecting said' pistonswitlrthecrankshaft, whereby the charge is compelled to flowfrom the inlet: portto 'theitransfer port along a path which drains downwardly towards thebottom ofthe' crank-case1away from the said inlet and transfer ports,and'liquid-collectin'gi pockets are "obviated, substantially asdescribed;

4. Ina horizontal,two-stroke cycle, internal-combustion engine of thethree-port type having crank-case compression of the combustiblemixture, the combination of a casing having a compression chamber in theform of a crank-case therein, a' pair of parallel horizontal cylinderswithin said'casing, whereof one cylinder is arranged vertically abovethe other, and both open at one end into said crank-case, a combustionchamber common to both cylinders at the end thereof remote from thecrank-case, the lower cylinder having an inlet port and at the sidethereof remote from the crankcase an exhaust port, the upper cylinderhaving in its upper part a transfer port and a transfer conduit whichcommunicates with the upper part of the crank-case, pistons operable onein each cylinder and arranged to control said ports, and means forcontrolling said pistons in unison, whereby the charge is compelled toenter the compression chamber at a part thereof situated below thecrankcase end of the transfer conduit, and the exhaust from the uppercylinder is compelled to pass through a part of the lower cylinder onits way to the exhaust port without encountering liquid-collectingpockets, substantially as described.

5. In a horizontal, four-cylinder, twostroke cycle internal-combustionengine of the three-port type having crank-case compression of thecombustible mixture, the combination of a casing having two compressionchambers each constituting a crankcase therein, two pairs of parallelhorizontal cylinders arranged side by side within said casing, whereofthe one cylinder of. one pair is arranged above the other cylinder ofthe same pair and both cylinders of a pair open at one end into one ofsaid crank-cases, two combustion-chambers, one common to each pair ofcylinders, at the end of the casing remote from the crank-case, the\lower cylinder of each pair having only in its upper part a fuel-inletport and in its lower part at the side thereof remote from thecrank-case an exhaust port, the upper cylinder of each pair havingatransfer port which communicates, with the upper part of the allottedcrank-case, pistons operable one in each cylinder and arranged tocontrol said ports, means for controlling said pistons, a supply chamberfor combustible mixture situated between said cylinders and openingdirectly into said inlet ports, and a horizontal supply conduit forcombustible mixture substantially parallel to the axes of the fourcylinders and free from pockets lying between said cylinders and openinginto said supply chamber, substantially as described. s

6. In a horizontal, four-cylinder twostroke cycle, internal-combustionengine of the three-port type having crankcase compression with thecombustible mixture, the combination of a casing havingtwo compressionchambers each constituting a crankcase therein, two pairs of parallelhorizontal cylinders arranged side by side within said casing, whereofthe one cylinder of one pair is arranged above the other cylinder of thesame pair and both cylinders of a pair open at one end into one of saidcrank-- cases, two combustion chambers, one common to each pair ofcylinders, at the end of the casing remote from the crank-case, thelower cylinder of each pair having only in its upper part an inlet portand in its lower part at the side of said inlet port remote from thecrank-case an exhaust port, the upper cylinder of each pair having atransfer port which communicates with the upper part of the allottedcrank-case, pistons operable one in each cylinder and arranged tocontrol said ports, means for controlling said pistons, a supply chamberfor combustible mixture situated between said cylinders and openingdirectly into said inlet ports, the wall of which supplychamber isconstituted in part by parts of the walls of said cylinders, and asupply conduit for comliustible mixture free from pockets lying betweensaid cylinders and opening into said supply chamber, whereby thecombustible mixture will be heated by the cylinders on its way to thelatter, substantially as described. a

In testimony whereof I affix 'my signature.

LESLIE HAYWOOD HOUNSFIELD.

